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Replacement Solar System on a Yacht 48v vs 12v panels - Sourcing Panels

AdventurePeter

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Jun 20, 2022
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Hi All,

I have an older yacht in Australia where i would like to replace the current solar system. The batteries are 12v. There is limited room on a yacht for solar Panels. I can fit four larger panels only (say 4 X 380w = 1520w). To minimise shading issues and maximise output i will use one MPPT controller per solar panel. This will also allow easier migration to Lithium as i can move one or more MPPT controllers to a new lithium battery bank over time moving off AGM batteries (will require additional cabling but there would be a controller per panel to allow for Lithium battery configuration for the controllers connected to lithium.) The distance from the panels to the the location of the proposed solar controllers and batteries is about 13m. I would like to get 48v panels as this will significantly reduce the size of the wires required for the 13m run to the preferred location of MPPT controllers near the batteries. The solar controllers output would go to a pos and neg bus bar then will run max amp cables to the batteries and shunt.

I am trying to find 48v 350w/380w solar panels similar to the many 350w/380w 12v panels being offered on Australian ebay/amazon etc. The 380w 12v panels weight is around 12kg and are 157cm X 77cm X 3.5cm which are about the largest i can fit in the limited available space.

So I am trying to find if there are any 48v Solar panels of a similar wattage, weight and size to the 12v panels that are readily available. I found only a small number of 48v panels and these were around twice the weight of the 12V panels (less weight is helpful on a yacht).

An alternative to 48v Panels would be to use the readily available 12v panels and deal with the higher amps. I would locate the 4 MPPT controllers close the panels to keep wire size small (2.5m for example). Have 4 solar disconnect switches and fuses, and then a common high amp positive and negative bus bar on the output side of the controllers, located close to the controllers. Then run large max amp cables from the bus bars about 11m to the batteries and shunt.

The 48v solution seems more ideal as the amps for the solar controllers will be less (less cost for controllers) and the cable sizes less, and the location of the controllers would be more ideal. Strange there are few 48v panels easily available in Australia (or I dont know where to find them like i can find 12v panels)

Thanks for any suggestions.
 
You can easily get ~400W "24V" panels (they usually have a Voc of some 40V, some 32V under load).
Around here they are some €160 and about 170X110 cm.
For more voltage you can series them two by two.-
Thanks for your response.

The challenge with a Yacht compared to most things with solar panels, is the boat is facing all different directions at anchor and that there is rigging, sails, aerials, wind generators, masts etc that can all shade panels. And two there is limited room for panels on a boat. So the panels you add to a boat need to be the most efficient possible dealing with shading. The best is one MPPT controller per panel,. Both Series and Parallel both have differing effects of shading and annoyingly many yachts will have significant and constant shading throughout the day. Also every scrap of efficiency is needed as the alternative to Solar and Wind (and Hydro generation) involves diesel and fossil fuels. The dream of a Yachite (like off grid) is to be as energy self-sufficient as possible allowing extended adventures not constrained by basic power needs.
 
Yeah well. I've lived (all year round, not just summer cruising) on small sailboats for half my life.
I wouldn't worry about shading all that much. If you can fit four of those on your boat, they'll give you plenty of charge.
Obviously four separate controllers are best for efficiency. But not all that much.
Wind, if you can get it at night, and have the budget for a couple of good quality generators, will supplement them nicely.

But the main things are,
1) those new-generation panels are really quite efficient, and
2) the real key to self-sufficiency at sea is reasonable/clever consumption. :·)
-
 
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